Highlight: "In this case, they had a range of mood and behavior problems, and what we call executive dysfunction, or problems with initiating and planning, organization. So we weren't looking at the brain, per se, in this study. We've done that in the past with another study looking at this age of starting to play where we actually had brain scans. But in this case it was just how are they functioning, what are their symptoms like as adults?

"And the answer is that these folks who started to play tackle football before age 12 had a threefold increased odds of having clinically meaningful depression symptoms and twofold clinically meaningful apathy and behavioral dysregulation, meaning not being able to control their behaviors and their impulses, as well as self-reported difficulties with this executive functioning."